The invention relates generally to welding systems and, more particularly, to strip cladding heads and strip cladding systems.
Cladding is a fundamental process to the manufacturing and fabrication industries and is used across many applications, including petrochemical, oil and gas, pressure vessel and boiler making. The process of cladding involves putting a new layer on top of an existing work piece (e.g., to repair items such as nozzles, ball valves, mill rolls and shafts) and/or to improve the wear resistance or corrosion properties of the piece. Cladding methods include submerged arc strip cladding (SASC) and electroslag strip cladding (ESSC).
In conventional SASC, an arc runs along the width of the strip, depositing weld metal on the base material. Because there is penetration into the base material, dilution levels typically are about 20 percent with SASC.
In conventional ESSC, the strip is fed through a delivery system much like wire is fed during a conventional wire welding process. Since ESSC is not an arc process, heating takes place in the conductive flux, and the resulting heating effect melts the strip and base material into the liquid slag, which is then transferred into molten metal that is deposited onto the base material. The strip rides on top of the slag system created by the flux, protecting the weld.